Radioreceiving system



E. F. W.- ALEXANDERSON.

RADIORECEIVI NG SYSTEM. APPLICATION FILED AUG-25, I917.

1,350,912, Patented Aug. 24,1920.

Inventor: Ernst F.W.A|exanderson,

H is Attorneg.

. umrsn STATE-S.

PATENT 0m ST rnxmnnnson, or scnhnncrsnv, NEW YORK, ASSIGNOR 'ro Grimmer. nnnc'rnrc comrANY, GoRPpRA'rIon or NEW YORK.

RADIOB-ECEIVIN SYSTEM.

Application filed August 25, 1917. Serial No. 188,109.

To all whom it may concern 3 I.

Be it known that I, ERNST F. W. ALEXAN- DERSON, a.- citizen of the United States,'residingat Schenectad in the county of Schenectady, State of ew York, have invented certain new and useful Improvements in Radioreceiving Systems, of which the following is a specification.

present invention relates to radio signaling systems and particularly to a receiving system'for radio messages.

The object of. my invention is to provide a receiving system which will permit of the receiving of messages from a distant station at the same time that messages are being transmitted from a station at or near which the receiving apparatus is located.

In carrying my invention into effect I employ a coil of wire for receiving the waves coming from the distant station and locate this coil in a vertical lane passing through the distant station. his coil is connected in a circuit which is tuned to the frequency of the waves to be received. Under these conditions although av local station at or near which the receiving coil is located may be transmitting waves of a different frequency enough energy may be received therefrom by the receiving coil to completely drown out the eifect of the des1red waves. To overcome this difiiculty. I associate with the first coil a second coil which is preferably located at substantially right angles to the first coil and connect this in a circuit which is tuned to the frequency of the waves transmitted from the local station. This coil will absorb energy ofthe local Waves, and prevent the local waves from interfering with the reception of the desired waves in the receiving coil.

p novel features which I believe 'to be characteristic of my invention are pointed.

out .With particularity in the appended claims. My invention itself however will be best understood by reference to the accompanying drawing in which I have indicated diagrammatically a manner whereby it may be carried into effect.

In the drawing the local transmitting station-is indicated by the antenna tower land the distant station from which messages are to be receivedby the antenna tower 2. The

coil 3 which comprises a number of turns of wireand is preferably 0f'1e0-.".- tangular shapemaybe located 1n a plane thewavesfrom theneaihystation.

passing through the distant station 2. This coil is connected in the tuned grid circuit of an electron dlscharge detector 4 comprising the usual filamentary cathode 5, anode 6,

and grid 7 inclosed in an exhausted receptacle. The grid circuit is tuned to the frequency of the waves to be received by means of the variable condenser 8. While I have indicated this particular form of detector it will of course be apparent that any other and is associated with the first coil in such a way as to screen it from theflect of the local waves or neutralize the effect of those waves in the receiving coil. In the present case the second coil 9 is located at a right angle to the coil 3 and the circuit on which the coil 9 is included is tuned by means of inductance 10 and capacity 11 to the frequency '-of the waves transmitted from station 1. This coil will absorb energy'from station 1 which comes within the field of coil 3 and prevent the setting up of undesirable currents in the receiving circuits. B the means which I have described it will be possible to transmit and receive messages simultaneously at a given point without locating the receiving apparatus at a distance' from the transmitting apparatus.

What I claim as new and desire to secure by Letters Patent of the United States, is: D l. Means for preventing the'efi'ect upon radio receiving apparatus of waves transmitted from a nearby station comprising a receiving coil located in a plane passing .through a distant. station from which messages are to be received, said coil being connected a circuitfwhich is resonant to the frequency of the waves to .be received and a 'second coil located at substantially a right anglepto the fir'St coil and connected in" a circ-uit which is-i re'sonant t therfrequency of 2. Means for receiving radio signals comprising a coil located in a plane passing through a station from which signals are to be received, said coil being connected in a circuit which is resonant to the frequency of the Waves to be received and a second coil located at an angle to the first coil and connected in a circuit which is resonant to a different frequency.

3. Means for receiving radio signals comprising a 18C61V1I1g001l connected in a circuit which 1s resonant to the frequency of Waves which are to be received and a second receiving coil connected in a circuit which is resonant to waves of a'difi'erent frequency, said second coil 'being associated with the first coil in such a way that it will prevent waves of the frequency for which it is resonant from interfering with the reception I of waves of the frequency for which the circuit of the first coil is tuned.

In Witness whereof I have hereunto set hand this 24th day of Augfiigtfi 1917.

y v 'ERNS'JF F. W. ALEXA RSON. 

